Detection of displayport alternate mode communication and connector plug orientation without use of a power distribution controller

ABSTRACT

This disclosure generally relates to USB TYPE-C, and, in particular, DISPLAYPORT Alternate Mode communication in a USB TYPE-C environment. In one embodiment, a device determines a DISPLAYPORT mode and determines an orientation of a USB TYPE-C connector plug. A multiplexer multiplexes a DISPLAYPORT transmission based in part on the determined orientation of the USB TYPE-C connector plug.

TECHNICAL FIELD

This disclosure generally relates to USB TYPE-C, and, in particular,DISPLAYPORT Alternate Mode communication in a USB TYPE-C environment.

BACKGROUND

Universal Serial Bus (USB) is a peripheral interface for attaching awide variety of computing devices, such as personal computers, digitaltelephone lines, monitors, modems, mice, printers, scanners, gamecontrollers, keyboards, storage devices, and/or the like.

USB TYPE-C is a new standard under the USB umbrella. The USB TYPE-Cconnector supports power, data, and video at the same time. The TYPE-Cconnector supports up to 100 W of power delivery, up to 10 Gbps of USBSuperSpeed+ (SS+) data transfer and up to 8.1 Gbps of DISPLAYPORTAlternate Mode (DP Alt Mode) video. In addition to DP Alt Mode video,the TYPE-C connector supports various other DP Alt Mode video and datastandards such as MHL, HDMI, and THUNDERBOLT.

The USB TYPE-C device that passes information through the USB TYPE-Cconnector and, specifically, the multiplexer in the USB TYPE-C devicerelies heavily on the Power Distribution (PD) controller to successfullyperform operations. For that reason, the PD controller has to controlthe multiplexer through a control interface or directly throughconfiguration pins. This type of operation imposes a hardware andsoftware burden on the multiplexer and the PD controller. Moreover,dedicated pins need to be made available for the control interface onboth the PD controller and the multiplexer, and the PD Controller needsto include the multiplexer in its firmware and other programmingresources. Also, in the scenario of remote daughter cards, cables, ormodules, long and cost-inefficient cabling may be required to connectthe PD controller and the multiplexer.

SUMMARY OF PARTICULAR EMBODIMENTS

In accordance with this disclosure, a device determines a DISPLAYPORTmode and determines an orientation of a Universal Serial Bus (USB)TYPE-C connector plug. A multiplexer multiplexes a DISPLAYPORTtransmission based in part on the determined orientation of the USBTYPE-C connector plug.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a system architecture of a USB TYPE-C source deviceexchanging information with a USB TYPE-C sink device over a USB TYPE-Cconnector.

FIG. 2 illustrates a USB TYPE-C connector pinout.

FIG. 3 illustrates a connection between a USB TYPE-C source device and aUSB TYPE-C sink device in a normal connector plug orientation.

FIG. 4 illustrates a connection between a USB TYPE-C source device and aUSB TYPE-C sink device in an inverted connector plug orientation.

FIG. 5 illustrates an example method for detecting a DISPLAYPORTAlternate Mode transmission and connector plug orientation.

DESCRIPTION OF EXAMPLE EMBODIMENTS

The disclosure describes one or more methods for automatically detectinga Universal Serial Bus (USB) TYPE-C DISPLAYPORT Alternate Mode andorientation of a connector. In one embodiment, a device determines aDISPLAYPORT mode and determines an orientation of a USB TYPE-C connectorplug. A multiplexer multiplexes a DISPLAYPORT transmission based in parton the determined orientation of the USB TYPE-C connector plug.

The disclosure may present several technical advantages. Technicaladvantages of the method may include reducing the amount of hardwareresources, such as configuration pins on both the Power Distribution(PD) controller and the multiplexer and reducing the need for longcabling between both devices. Reducing the amount of hardware resourcesmay also reduce the form size of the USB TYPE-C device. Anothertechnical advantage of the method may include relieving the softwareburden on the PD controller and also the USB TYPE-C device.

FIG. 1 illustrates system architecture 100 of USB TYPE-C source device110 exchanging information with USB TYPE-C sink device 130 over USBTYPE-C connector 120.

As illustrated, source device 110 includes auto detection device 140 a,multiplexer 142 a, PD controller 144 a, receptacle 146 a, power supply148 a, USB device 150 a, and DISPLAYPORT (DP) source 152. Source device110 may include any device that is USB TYPE-C compatible, and maytransmit DISPLAYPORT Alternate Mode (DP Alt Mode) information to sinkdevice 130. Moreover, source device 110 may receive DP Alt Modeinformation from sink device 130.

Likewise, as illustrated, sink device 130 includes auto detection device140 b, multiplexer 142 b, PD controller 144 b, receptacle 146 b, powersupply 148 b, USB device 150 b, and DP sink 154. Sink device 130 mayinclude any device that is USB TYPE-C compatible, and may receive DP AltMode information to source device 130. Moreover, sink device 130 maytransmit DP Alt Mode information to source device 110.

Auto detection device 140 may comprise any device, circuitry, and/orlogic that detects a DP Alt Mode and also detect the orientation of theplug. While illustrated as a separate component from multiplexer 142,auto detection device 140 may be incorporated in multiplexer 142, PDcontroller 144, and/or any other device, circuitry, and/or logicincluded in source device 110. In certain embodiments, auto detectiondevice 140 is external to source device 110. Auto detection device 140may be similar when implemented in source device 110 (e.g., autodetection device 140 a) or sink device 130 (e.g., auto detection device140 b).

Multiplexer 142 may comprise any device, circuitry, and/or logic thatselects one of several input signals and multiplexes the selected inputto its proper internal port. Multiplexer 142 may help transfer signalsreceived by receptacle 146 and may properly transfer that signal to USBhost 150 and/or DP Alt Mode source 152. As explained in further detailbelow, multiplexer 142 may change the multiplexing of one or morereceived signals based on the connector plug orientation of connector120. Multiplexer 142 may be similar when implemented in source device110 (e.g., multiplexer 142 a) or sink device 130 (e.g., multiplexer 142b).

In particular, multiplexer 142 connects sideband signaling (e.g., firstsideband (SBU1) signal and second sideband (SBU2) signal) to itsrespective positive auxiliary and/or negative auxiliary ports. Forexample, multiplexer 142 may connect SBU1 and SBU2 signaling to itsrespective positive and/or negative auxiliary ports based on whether thedevice is a source or sink device and based on whether the connectorplug orientation is normal or inverted. Specifically, multiplexer 142may connect SBU1 and SBU2 signaling to its respective positive and/ornegative auxiliary ports in the following manner:

TABLE 1 Transmission Based on Connector Orientation Source Sink NormalFlipped Normal Flipped Orientation Orientation Orientation OrientationSBU1 → AUXp SBU1 → AUXn SBU1 → AUXn SBU1 → AUXp SBU2 → AUXn SBU2 → AUXpSBU2 → AUXp SBU2 → AUXn

Directing data, video, and AUX signals to appropriate TYPE-C connectorpins based on TYPE-C connector plug orientation and the location of theTYPE-C port (downstream facing port or an upstream facing port) isrequired to make the TYPE-C ecosystem work as intended. Conventionally,multiplexer 142 is needed to direct high-speed USB data, video, andauxiliary signaling to the appropriate pins. To properly complete thistask, multiplexer 142 must be aware of the presence or absence of a DPAlt Mode and detect the TYPE-C connector plug orientation.

PD controller 144 may implement functionalities defined in the USB PDspecification. Source device 110's host controller may manage andcontrol the PD controller for power delivery. The commands may becommunicated over a bus interface comprising a data line and a clockline. PD controller 144 may be similar when implemented in source device110 (e.g., PD controller 144 a) or sink device 130 (e.g., PD controller144 b).

Receptacle 146 may be any type of pinout that transmits and/or receivesdata, power, and/or video via connector 120. For example, receptacle 146a may transmit DP Alt Mode video information, USB data, and/or powerfrom source device 110 via connector 120. As another example, receptacle146 b may receive DP Alt Mode video information, USB data, and/or powerfor sink device 130 via connector 120. The pinouts in receptacle 146 areexplained in further detail in FIG. 2. Receptacle 146 may be similarwhen implemented in source device 110 (e.g., receptacle 146 a) or sinkdevice 130 (e.g., receptacle 146 b).

USB device 150 may be any type of device, circuitry, and/or logic thatis able to transmit and/or receive USB data. USB device 150 may besimilar when implemented in source device 110 (e.g., USB device 150 a)or sink device 130 (e.g., USB device 150 b).

DP source 152 may be any type of device, circuitry, and/or logic that isable to transmit and/or receive DP Alt Mode data and/or information. DPAlt Mode may leverage the alternate mode function of the USB TYPE-Cinterface, and may provide video, SuperSpeed USB, and power all in oneconnector.

Connector 120 may be any type of connector that connects source device110 and sink device 130. In particular, connector 120 plugs intoreceptacle 146 a of source device 110 and receptacle 146 b of sinkdevice 130. Connector 120 supports the transfer of data, power, and/orvideo using the USB TYPE-C protocol. In particular connector 120 is ableto support alt mode applications. Connector 120 may be reversible inthat each end of the connector is able to plug into receptacle 146 a ofsource device 110 and/or receptacle 146 b of sink device 130. Moreover,connector 120 is able to be plugged into receptacle 146 in either anormal or inverted orientation.

As illustrated, source device 110 includes auto detection device 140 a,multiplexer 142 a, receptacle 146 a, power supply 148 a, USB device 150a, and DP source 152. Source device 110 may include any device that isUSB TYPE-C compatible, and may receive DP Alt Mode information from sinkdevice 110.

Likewise, as illustrated, sink device 130 includes auto detection device140 b, multiplexer 142 b, receptacle 146 b, power supply 148 b, USBdevice 150 b, and DP sink 154. Sink device 130 may include any devicethat is USB TYPE-C compatible, and may receive DP Alt Mode informationfrom source device 110.

In an exemplary embodiment, multiplexer 142 may not receive signalingfrom PD controller 142, and, in particular, multiplexer 142 may notreceive signaling from PD controller 142 indicating whether DP Alt Modeis present and/or the connector plug orientation of connector 120.Instead, auto detection device 140 may indicate to multiplexer 142whether DP Alt Mode is present and/or the connector plug orientation ofconnector 120. In certain embodiments, source device 110 and/or sinkdevice 130 may not comprise a PD controller 144. In certain embodiments,source device 110 and/or sink device 130 may comprise a PD controller144, but PD controller 144 may not indicate to multiplexer 142 whetherDP Alt Mode is present and/or the connector plug orientation ofconnector 120. Moreover, in certain embodiments, auto detection device140 may be incorporated into multiplexer 142, or auto detection device140 may be separate from multiplexer 142.

Auto detection device 140 determines the presence or absence of a DP AltMode by detecting a received signal on either the SBU1 pin or SBU2 pin.In certain embodiments, SBU1 and/or SBU2 only support the transmissionof DP Alt Mode signals. Specifically, SBU1 and/or SBU2 may only be usedas a DP Alt Mode auxiliary signal channeling in certain embodiments.Consequently, when auto detection device 140 determines the signal isbeing received on the SBU1 pin and/or SBU2 pin, auto detection device140 may infer that a device that supports DP Alt Mode is connected.

In certain embodiments, auto detection device 140 detects the presenceand/or absence of DP Alt Mode by detecting a reception of one or moresignals in either the SBU1 pin or SBU2 pin of the device. In certainembodiments, auto detection device 140 may detect a transmitted signalin the positive auxiliary that is connected to either the SBU1 pin orSBU2 pin and/or in the negative auxiliary that is connected to eitherthe SBU1 pin of SBU2 pin.

Moreover, auto detection device 140 may detect a received signal ineither the SBU1 pin or the SBU2 pin by detecting a pull up (e.g., a highvoltage) on the SBU1 pin or SBU2 pin. For example, in auto detectiondevice 140 in source device 110, auto detection device 140 may detect atransmitted signal by detecting a high voltage on the SBU1 pinindicating a signal transmission via a pull-up resistor. Similarly, inauto detection device 140 in sink device 130, auto detection device 140may detect a signal transmission by detecting a high voltage on the SBU2pin indicating a signal transmission via a pull-up resistor.

In certain embodiments, auto detection device 140 and/or multiplexer 142may know whether the auto detection device 140 and/or multiplexer 142 isin a source device or sink device via a pin, memory, and/or register inthe device.

In certain embodiments, the auxiliary signal may not be transmitted toauto detection device 140. In this embodiment, auto detection device 140snoops the USB data line to determine display port mode. The USB dataline may use low frequency polling signaling before transmitting the USBdata. For transmitting DP Alt Mode information, however, the USB dataline may not communicate a low frequency polling signaling. Accordingly,auto detection device 140 may detect a high-speed signal without lowfrequency periodic signaling signals and, therefore, determine that DPAlt Mode information is then being sent across the USB data line. Bysubmitting DP Alt Mode information across USB data line, auto detectiondevice 140 determines that the communication is DP Alt Mode four-lane.DP Alt Mode four-lane can carry four DISPLAYPORT lanes across connector120. In certain embodiments, auto detection device 140 may detect alow-speed signal and low frequency periodic signaling signals, and,therefore, determine that DP Alt Mode information is not being sentacross USB data line. Because USB data line is not transmitting DP AltMode information, auto detection device 140 determines that thecommunication is either DP Alt Mode one-lane or DP Alt Mode two-lane.Unlike DP Alt Mode four-lane, DP Alt Mode two-lane can carry twoDISPLAYPORT lanes across connector 120 and DP Alt Mode one-lane can onlycarry one DISPLAYPORT lane across connector 120.

Auto detection device 140 may also determine the connector plugorientation based on the type of signal transmission on SBU1 and/orSBU2. Based on the type of signal transmission on SBU1 and/or SBU2 atthe positive auxiliary and/or the negative auxiliary, auto detectiondevice 140 may determine the connector plug orientation. For example,auto detection device 140 in source device 110 may detect that the SBU1signal is communicated to the positive auxiliary. Accordingly, autodetection device 140 may then be able to detect that connector 120 isconnected to the normal orientation. Likewise, auto detection device 140in source device 110 may detect that SBU1 is communicated to thenegative auxiliary. Accordingly, auto detection device 140 may then beable to detect that connector 120 is connected in an invertedorientation. Moreover, as another example, auto detection device 140 insink device 130 may detect that the SBU1 signal is communicated to thenegative auxiliary. Auto detection device 140 may then detect theconnector 120 is in a normal orientation. As a final example, autodetection device 140 may detect that the SBU1 signal is communicated tothe positive auxiliary, and, accordingly, auto detection device 140 maythen the deduce that connector 120 is in an inverted orientation.

The following table illustrates an exemplary embodiment of theconditions used by auto deduction device 140 to determine theorientation of connector 120:

TABLE 2 Exemplary Logic for Determining Connector Orientation SOURCESINK SBU1 → AUXp Normal Orientation Inverted Orientation SBU2 → AUXnSBU1 → AUXn Inverted Orientation Normal Orientation SBU2 → AUXp

In certain embodiments, auto detection device 140 may detect thepresence of the DP Alt Mode and/or orientation of connector 120 based onsnooping the auxiliary signal. As discussed earlier, whenever DP AltMode is present, the DP Alt Mode signals are communicated over theauxiliary channel. By performing auxiliary channel snooping, thepresence of DP Alt Mode is established when a valid auxiliary isdetected. In certain embodiments, the orientation of connector 120 isdetermined by analyzing the preamble of the auxiliary signal.

Moreover, the orientation can be detected through a Manchester decodingscheme of either the positive auxiliary and negative auxiliary signal.First, auto detection device 140 analyzes a number of clock cycles(e.g., 28 clock cycles) to determine a current state of the auxiliarysignal. At this point, a state machine for auto detection device 140 isin Acquire Mode.

After a number of clock cycles pass, the state machine for autodetection device 140 moves to Sync High State mode. In Sync High Statemode, the Manchester logic is searching for a Manchester violation inthe auxiliary signal. A Manchester violation is a received signal levelthat is different than what auto detection device 140 anticipates. Forexample, if auto detection device 140 is anticipating a high auxiliarysignal because auto detection device 140 assumes the connector plugorientation is normal but, instead, receives a low auxiliary signal,then the auto detection device 140 detects a Manchester violation.Accordingly, auto detection device 140 knows that the connector 120 isinverted and sets an internal inverted orientation flag.

Auto detection device 140 may also reset its state machine if aManchester violation occurs. In certain embodiments, during the SyncHigh State mode, the only expected input is an input signal that isbetween 1 and 5 clock lengths. If a signal is received that is less than1 clock length or greater than 5 clock lengths, then a Manchesterviolation has occurred and auto detection device 140 may reset the statemachine.

The state machine may then move to Sync Low State mode. In Sync LowState mode, auto detection device 140 may anticipate a valid lowauxiliary signal. However, when the auxiliary signal changes to highagain, auto detection device 140 may set an internal invertedorientation flag, and the auxiliary signal inversion will be applied forthe remainder of the signal.

By determining whether the connector plug orientation is normal orinverted using the preamble of the auxiliary signal, the signal'spolarity has already been corrected by the time the first data bit inthe auxiliary signal arrives.

Another component that may determine the connector plug orientation isthe auxiliary port polarity. The auxiliary port polarity can berecognized based on the polarity of the first packet of the auxiliarysignal.

Moreover, by snooping the auxiliary signal, auto detection device 140can detect from the auxiliary signal the number of lanes transmitting DPAlt Mode. For example, the auxiliary signal data stream may indicatethat the DP Alt Mode signal is being transmitted on two lanes (i.e., DP2 Lane mode). As another example, the auxiliary signal data stream mayindicate DP Alt Mode signal is being transmitted on four lanes (i.e., DP4 Lane mode). In certain exceptional cases, auto detection device 140may activate DP 2. Lane Mode even if the auxiliary signal data streamindicates that only one lane is transmitting DP Alt Mode information.

Now, given the detection of the orientation of connector 120, thedetection of the transmitted DP Alt Mode signal, and knowledge ofwhether the device is a source device 110 or sink device 130,multiplexer 142 is then able to properly direct the input signals to theproper internal ports. For example, multiplexer 142 may multiplex one ormore DP signals based on the determined orientation of the USB TYPE-Cconnector plug. As another example, multiplexer 142 may multiplex thereceived signal at the SBU1 pin and/or SBU2 pin based on the determinedorientation of the USB TYPE-C connector plug. FIG. 3 and FIG. 4illustrates in further detail the proper multiplexing of receivedsignals by multiplexer 142 based on these variables.

Multiplexer 172 may multiplex the display port transmission differentlydepending on the orientation of USB TYPE-C connector 120. Similarly, thesignal received at the SBU1 pin and/or the SBU2 pin may be multiplexeddifferent depending on the orientation of the USB TYPE-C connector 120.

FIG. 2 illustrates a USB TYPE-C connector pinout 200. USB TYPE-Cconnector pinout 200 may be found in receptacle 146 of source device110, receptacle 146 of sink device 130, and/or connector plug ofconnector 120. In the illustrated embodiment, connector pinout 200comprises ground pins 210 a-d, TX1+/−signal pins 212 a-b, RX1+/−signalpins 213 a-b, bus power pin 214 a-d, configuration channel pins 216 a-b,USB data pins 218 a-d, sideband pins 220 a-b, RX2+/−signal pins 222 a-b,and TX2+/−signal pins 223 a-b.

In normal TYPE-C connector plug orientation, USB data passes throughTX1+/−signal pins 212 a-b and RX1+/−signal pins 213 a-b, and, in theflipped connector plug orientation, USB data passes through TX2+/−signalpins 223 a-b and RX2+/−signal pins 222 a-b. When 2 lanes of DP Alt Modevideo are also transmitted along with USB data, in the normal TYPE-Cconnector plug orientation, DP Alt Mode video is channeled throughTX2+/−signal pins 223 a-b and RX2+/−signal pins 222 a-b, and, in theflipped connector plug orientation, USB data goes through TX1+/−signalpins 212 a-b and RX1+/−signal pins 213 a-b. If there is no USB data, allthe four differential pair pins (TX1+/−, RX1+/−, TX2+/−, and RX2+/−) canbe used to transfer four lanes of DP Alt Mode signals.

DP Alt Mode video also involves low-speed Auxiliary (AUX) signal that istransmitted through the sideband pins 220 a-b of the TYPE-C connector.In the illustrated Figure, sideband pin 220 a represents the SBU1 pinand sideband pin 220 b represents the SBU2 pin. AUX signal isdifferential with two single-ended signals of opposite polarity—positive(AUXP) and negative (AUXN). AUXP and AUXN are connected to either SBU1or SBU2 depending on the TYPE-C connector plug orientation and whetherthe TYPE-C connector is on a downstream facing port (DFP) or an upstreamfacing port (UFP).

FIG. 3 illustrates a connection between a USB TYPE-C source device and aUSB TYPE-C sink device in a normal connector plug orientation. In theillustrated embodiment, receptacle 146 a and receptacle 146 b share thesame pin layout as illustrated in FIG. 2. While illustrated as aseparate component, source device 110 may comprise auto detection device140 a, multiplexer 142 a, and/or PD controller 144 a. Similarly, whileillustrated as a separate component, sink device 130 may comprise autodetection device 140 b, multiplexer 142 b, and/or PD controller 144 b.

Moreover, by illustration, the connections between receptacle 146 a and146 b are represented by alphabetical indicators. Each alphabeticalindicator represents a connection between the two pins. For example, RX2222 in receptacle 146 a (as indicated by the letter ‘A’) is connected toTX2 223 in receptacle 146 b (as also indicated by the letter ‘A’).

As illustrated, in normal TYPE-C connector plug orientation for sourcedevice 110, USB data 320 a passes through TX1+/−signal pins 212 andRX1+/−signal pins 213 and, when 2 lanes of DP Alt Mode information 310 aare transmitted, the 2 lanes of DP Alt Mode information 310 a aretransmitted along TX2+/−signal pins 223 and RX2+/−signal pins 222. DPAlt Mode video also involves a low-speed AUX signal that getstransmitted through sideband pins 220. In normal TYPE-C connector plugorientation, AUXp 330 a is connected to SBU1 pin 220 a and AUXn 220 b isconnected to SBU2 pin 220 b.

As further illustrated, in normal TYPE-C connector plug orientation forsink device 130, USB data 320 b passes through TX1+/−signal pins 212 andRX1+/−signal pins 213 and, when 2 lanes of DP Alt Mode information 310 bare transmitted, the 2 lanes of DP Alt Mode information 310 a aretransmitted along TX2+/−signal pins 223 and RX2+/−signal pins 222.Similar to the DP Alt Mode video transferred on source side 110, DP AltMode video also involves a low-speed AUX signal that gets transmittedthrough sideband pins 220 a-b. In normal TYPE-C connector plugorientation, AUXp 330 b is connected to SBU2 pin 220 b and AUXn 340 b isconnected to SBU1 pin 220 a on sink device 130.

Given the detection of the orientation of connector 120, the detectionof the transmitted DP Alt Mode signal, knowledge of whether the deviceis a source device 110 or sink device 130, multiplexer 142 is then ableto properly direct the input signals to the proper output ports asillustrated in FIG. 3 for a normal connector plug orientation.

FIG. 4 illustrates a connection between a USB TYPE-C source device and aUSB TYPE-C sink device in an inverted connector plug orientation. In theillustrated embodiment, receptacle 146 a and receptacle 146 b share thesame pin layout as illustrated in FIG. 2. While illustrated as aseparate component, source device 110 may comprise auto detection device140 a, multiplexer 142 a, and/or PD controller 144 a. Similarly, whileillustrated as a separate component, sink device 130 may comprise autodetection device 140 b, multiplexer 142 b, and/or PD controller 144 b.

Moreover, by illustration, the connections between receptacle 146 a and146 b are represented by alphabetical indicators. Each alphabeticalindicator represents a connection between the two pins. For example, RX2222 a-b in receptacle 146 a (as indicated by the letter ‘A’) isconnected to TX2 223 a-b in receptacle 146 b (as also indicated by theletter ‘A’).

As illustrated, in an inverted TYPE-C connector plug orientation forsource device 110, USB data 320 a passes through TX2+/−signal pins 223a-b and RX2+/−signal pins 222 a-b and, when 2 lanes of DP Alt Modeinformation 310 a are transmitted, the 2 lanes of DP Alt Modeinformation 310 a are transmitted along TX1+/−signal pins 212 a-b andRX1+/−signal pins 213 a-b. DP Alt Mode video also involves a low-speedAUX signal that gets transmitted through sideband pins 220 a-b. Innormal TYPE-C connector plug orientation, AUXp 330 a is connected toSBU2 pin 220 b and AUXn 340 a is connected to SBU1 pin 220 a on sourcedevice 110.

As further illustrated, in an inverted TYPE-C connector plug orientationfor sink device 130, USB data 320 b passes through TX2+/−signal pins 223a-b and RX2+/−signal pins 222 a-b and, when 2 lanes of DP Alt Modeinformation 310 b are transmitted, the 2 lanes of DP Alt Modeinformation 310 a are transmitted along TX1+/−signal pins 212 a-b andRX1+/−signal pins 213 a-b. Similar to the DP Alt Mode video transferredon source side 110, DP Alt Mode video also involves a low-speed AUXsignal that gets transmitted through sideband pins 220 a-b. In aninverted TYPE-C connector plug orientation, AUXp 330 b is connected toSBU1 pin 220 a and AUXn 340 b is connected to SBU2 pin 220 b on sinkdevice 130.

Given the detection of the orientation of connector 120, the detectionof the transmitted DP Alt Mode signal, knowledge of whether the deviceis a source device 110 or sink device 130, multiplexer 142 is then ableto properly direct the input signals to the proper output ports asillustrated in FIG. 4 for an inverted connector plug orientation.

FIG. 5 illustrates example method 500 for detecting a DISPLAYPORTAlternate Mode transmission and connector plug orientation.

The method may begin at step 510, where a device determines aDISPLAYPORT Alt Mode by detecting a signal received on either the SBU1pin or the SBU2 pin. In certain embodiments, SBU1 pin and/or SBU2 pinonly support the transmission of DP Alt Mode signals. Specifically, SBU1and/or SBU2 may only be used as a DP Alt Mode auxiliary signal port incertain embodiments. Consequently, when auto detection device 140determines the signal is being received on SBU1 and/or SBU2, autodetection device 140 may infer that a device that supports DP Alt Modeis connected.

In certain embodiments, auto detection device 140 by detecting a highvoltage (i.e., a pull up) on the SBU1 pin or SBU2 pin. Alternatively,auto detection device 140 may detect a signal transmission by detectinga pull up on the positive auxiliary and/or negative auxiliary.

In addition, auto detection device 140 then detects a signaltransmission in the SBU1 pin or SBU2 pin. Moreover, in certainembodiments, auto detection device 140 and/or multiplexer 142 may knowwhether the auto detection device 140 and/or multiplexer 142 is in asource device or sink device via a pin, memory, and/or register in thedevice.

At step 520, auto detection device 140 may also determine the connectorplug orientation based on a signal transmission on SBU1 and/or SBU2.Based on the signal transmission on SBU1 at the positive or negativeauxiliary and/or SBU2 at the positive or negative auxiliary, autodetection device 140 may determine the connector plug orientation. Forexample, auto detection device 140 in source device 110 may detect thatthe SBU1 signal is communicated to the positive auxiliary. Accordingly,auto detection device 140 may then be able to detect that connector 120is connected to the normal orientation. Likewise, auto detection device140 in source device 110 may detect that SBU1 signal is communicated tothe negative auxiliary. Accordingly, auto detection device 140 may thenbe able to detect that connector 120 is connected in an invertedorientation. Moreover, as another example, auto detection device 140 insink device 130 may detect that the SBU1 signal is communicated to thenegative auxiliary. Auto detection device 140 may then detect theconnector 120 is in a normal orientation. As a final example, autodetection device 140 may detect that the SBU1 signal is communicated tothe positive auxiliary, and, accordingly, auto detection device 140 maythen the deduce that connector 120 is in an inverted orientation.

At step 530, multiplexer 142 multiplexes a DP signal based in part onthe determined orientation of the USB TYPE-C connector plug. At step540, multiplexer 142 multiplexes the SBU1 signal and/or the SBU2 signalbased in part on the determined orientation of the USB TYPE-C connectorplug.

In particular embodiments, one or more computer systems perform one ormore steps of one or more methods described or illustrated herein. Inparticular embodiments, one or more computer systems providefunctionality described or illustrated herein. In particularembodiments, software running on one or more computer systems on anon-transitory storage media performs one or more steps of one or moremethods described or illustrated herein or provides functionalitydescribed or illustrated herein. Particular embodiments include one ormore portions of one or more computer systems. Herein, reference to acomputer system may encompass a computing device, and vice versa, whereappropriate. Moreover, reference to a computer system may encompass oneor more computer systems, where appropriate.

What is claimed is:
 1. A method, comprising: determining, by a device, aDisplayPort mode by detecting a received signal on a first sideband use(SBU1) pin of the device or a second sideband use (SBU2) pin of thedevice; determining, by the device, an orientation of a USB Type-Cconnector plug by detecting a type of the received signal; multiplexing,by a multiplexer, a DisplayPort transmission based in part on thedetermined orientation of the USB Type-C connector plug; andmultiplexing, by the multiplexer, the received signal based in part onthe determined orientation of the USB Type-C connector plug.
 2. Amethod, comprising: determining, by a device, a DisplayPort mode bydetecting a received signal on a first sideband use (SBU1) pin of thedevice or a second sideband use (SBU2) pin of the device; determining,by the device, an orientation of a USB Type-C connector plug; andmultiplexing, by a multiplexer, a DisplayPort transmission based in parton the determined orientation of the USB Type-C connector plug.
 3. Themethod of claim 2, wherein detecting a received signal on a SBU1 pin ofthe device or a SBU2 pin of the device comprises detecting a pull up ineither the SBU1 pin or the SBU2 pin.
 4. The method of claim 2, furthercomprising multiplexing, by the multiplexer, the received signal basedin part on the determined orientation of the USB Type-C connector plug.5. The method of claim 2, wherein determining an orientation of a USBType-C connector plug comprises determining an orientation of a USBType-C connector plug by detecting a type of the received signal.
 6. Themethod of claim 2, wherein the device comprises one of the following: asource device coupled to a USB Type-C connector plug with a normalorientation; a source device coupled to a USB Type-C connector plug withan inverted orientation; a sink device coupled to a USB Type-C connectorplug with a normal orientation; or a sink device coupled to a USB Type-Cconnector plug with an inverted orientation.
 7. The method of claim 2,wherein the device does not comprise a PD controller.
 8. A system,comprising: a device configured to: determine a DisplayPort mode bydetecting a received signal on a first sideband use (SBU1) pin of thedevice or a second sideband use (SBU2) pin of the device; and determinean orientation of a USB Type-C connector plug; and a multiplexer coupledto the device, the multiplexer configured to multiplex a DisplayPorttransmission based in part on the determined orientation of the USBType-C connector plug.
 9. The system of claim 8, wherein detecting areceived signal on a SBU1 pin of the device or a SBU2 pin of the devicecomprises detecting a pull up in either the SBU1 pin or the SBU2 pin.10. The system of claim 8, wherein the multiplexer is further configuredto multiplex the received signal based in part on the determinedorientation of the USB Type-C connector plug.
 11. The system of claim 8,wherein determining an orientation of a USB Type-C connector plugcomprises determining an orientation of a USB Type-C connector plug bydetecting a type of the received signal.
 12. The system of claim 8,wherein the device comprises one of the following: a source devicecoupled to a USB Type-C connector plug with a normal orientation; asource device coupled to a USB Type-C connector plug with an invertedorientation; a sink device coupled to a USB Type-C connector plug with anormal orientation; or a sink device coupled to a USB Type-C connectorplug with an inverted orientation.
 13. The system of claim 8, whereinthe device does not comprise a PD controller.
 14. One or morecomputer-readable non-transitory storage media embodying software thatis operable when executed to: determine a DisplayPort mode by detectinga received signal on a first sideband use (SBU1) pin of the device or asecond sideband use (SBU2) pin of the device; determine an orientationof a USB Type-C connector plug; and multiplex a DisplayPort transmissionbased in part on the determined orientation of the USB Type-C connectorplug.
 15. The media of claim 14, wherein detecting a received signal ona SBU1 pin of the device or a SBU2 pin of the device comprises detectinga pull up in either the SBU1 pin or the SBU2 pin.
 16. The media of claim14, wherein the software is further operable when executed to multiplexthe received signal based in part on the determined orientation of theUSB Type-C connector plug.
 17. The media of claim 14, whereindetermining an orientation of a USB Type-C connector plug comprisesdetermining an orientation of a USB Type-C connector plug by detecting atype of the received signal.